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`(Model.)` R. SMITH.

ATTAC:HMT.:NT FOR GALGULATING SCALES Patented Peb. 8, 1887.

UNITED STATES PATENT OFFICE.

RUDOLPH C. SMITH, OF YONKERS, NEI/V YORK.

ATTACHMENT FOR CALCULATlNG-SCALES.

SPECIFICATION forming part of Letters Patent No. 357,346, dated February 8, 1887.

Application filed May 5, 1886. Sexial No. 201,200. (Mcrleh) To a/ZZ whom it may concern.-

Be it known that I, RUDOLPH C. SMITH, of Yonkers, in the county of Vestchester and State of New York, have iuvented'certain new and useful Improvements in Attachments for Calculating-Scales, ofwhich the following is a specification.

This invention has reference to an improved attachment for calculatingscales, by which a number of formulastrips are retained at the under side of the scale in longitudinal direction, so as to be conveniently carried in the lpocket, or quickly set at right angles, or at any other angle thereto, so as to facilitate the use of each individual strip in connection with the scale for purposes of computation, the formulev being read from the strips in the same manner as they are now read from the book or table. For example, when a calculation is to be made'of the weight of cast-iron, the strips are swung at right angles to the scale and the calculation made on the scale made on the scale according to the formulte given. The formulae are thus close to the scale and the eye need not travel a-great distance from one to the other. Considerable time is 10st in reading the formulae from a hand- .book and then making the calculations. Be-

sides, the strips can be folded and occupy much less space than a hand-book would. The formulae are printed transversely on the strips, so that the formul on the strips will be parallel with the scale. While using said strips the strips are swung into a position at right angles to the scale, as set forth, thereby facilitating the reading of the formulae.

The invention consists of the combination, with a calculatingscale, of a sleeveshaped spring-clasp that is connected by a joint with the scale, said sleeve supporting the 'formulastrips that are used in connection with the scale.

In the accompanying drawings, Figure l Vrepresents a perspective view of a calculatingscale with my improved attachment. showing the scale bottomupward. Fig. 2 is a bottom View of the scale and attachment. Fig. 8 is a top view ofthe scale, showing the formulastrips in position for use.

Fig. 4 is avertical transverse section online x x, Fig. 2; and Fig. 5 is a detail side view of the joint between the scale and sleeve.

Similar letters of reference indicate corresponding parts.

In the drawings,A represents a calculatingscale, preferably a logarithmic scale, of any approved construction. To the under side of the scale is applied astaple, c, to which is connected by perforated ears b b a sleeve-shaped clasp,B,of sheet metal, which binds by spring action upon a number of formulastrips, C, that are made of card-board, wood, metal, or other material and printed at both sides with formulae and instructions for the use of the strips in connection with the calculatingscale. The staple and perforated ears form a joint by which the formula-strips may be adjusted either longitudinally in line with the bottom of the scale, or at right angles or other angle to the same when the scale is to be used for calculating purposes. Vhen the other side of any of the strips is to be used,the sleeve B is turned on the staple, so as to reverse the strips and expose the other side of the same to View, as shown in Fig. 3.

Vhen one of thelower strips C is to be used, the upper strips may be moved in longitudinal direction in .the sleeve Vuntil they clear the strip that is desired to be used, or they may be spread apart, like the leaves of a fan, so as to exhibit the greater part of the lower strips.

In place of thejoint shown, analogous constructionsofjoints may be used, .as the special construction is immaterial, provided that it permits the change of position of the formulastrips from their position in line with the scale to a position at an angle thereto, and also the strips can be reversed. The sleeve is preferably made of sheet .metal in such a manner that a spring-pressure is exerted on the strips, so that they are prevented from shifting in the sleeve. The formula-strips are thereby conveniently carried with the scale and always ready for use whenever required, and form a convenient andl effective attachment or auxiliary to the calculating-scale.

Having thus described my invention, I claim as new and desire to secure by Letters Patent- 1. The combination of a scale, a sleeve- IOO shaped springelasp jointed to said scale', and formulavstrps supported by said clasp, substantially as set forth.

2. The combination, with a calculating-scale,

' of a sleeveshaped clasp, a joint connecting the scale and sieeve,and formula. strips supported n said elaspaid forr'nulafstrps being adapted to be placed in line With the seale, or at any angle thereto, substantially as set forth.

3. The combination of a ealculatingscale having a fixed staple, a spring sleeve or clasp eonneeted by perforated ears with said staple, and formula-Strips supported in said sleeve or clasp,substantia1ly as set forth.

In testimony that I claim the foregoing as 15 my invention I have signed my name in presence of two subscribing Witnesses.

RUDOLPH G. SMITH.

Witnesses:

PAUL GOE'PEL, MARTIN PETRY. 

